RF Problem Transmission Analysis Process: VS.RAB.FailEstPS.TNL

RF Problem: Check coverage in the failure points. Check if it is in cell border (most probably it is).

Congestion Problem: Check the Admission Control thresholds. Take appropriate measures to increase capacity.

KPI(3): High DCR CS

Check the unavailability or faults at problematic sites and its neighboring sites. Check the distribution of call drops in the network; happens in specific areas or whole area. Check the traffic distribution in the problematic areas. Check if there was an abnormal increase of the traffic due to some event.

Problem Classification RF Problem

Abnormal Release Indicator

Note

VS.RAB.AbnormRel.CS.UTRANgen Non-RF Problem

VS.RAB.AbnormRel.CS.OLC

VS.RAB.AbnormRel.CS.IuAAL2

CS RAB drops due to OM intervention, e.g. cell was blocked CS RAB drops due to preemption CS RAB drops due to UTRAN generated reasons; indicates hardware failure on RAN equipment; check alarms in order to identify the faulty part; repair or replace the faulty part once identified. Released Due to congestion for Cell CS RAB drops due to AAL2 failure; check transmission alarms to identify possible faults in the Iu-CS transmission path

Analysis Process: DCR CD (RF Problem): Check for missing neighbors Check for pilot pollution (adjust physical config) Check for UL interference. Check VS.MeanRTWP counter in order to see the value of UL interference in the cell. If the value is higher than -97 dBm, then interference exists in the UL. o Check internal interference: Internal interference is usually caused by faulty connections in the antenna line. Check thoroughly all relative connection o Check external interference: External interference is caused by external sources (e.g. TV/Radio stations, military equipment, other networks equipment, etc.). External interference will appear randomly throughout the day. Its direction will be specific and it will affect more than one sites in the area. Check neighboring sites to see if they face the same problem. In case of poor coverage, adjust physical config.

PS RAB drops due to RLC reset PS RAB drops due to OM intervention, e.g. cell was blocked PS RAB drops due to preemption Released Due to congestion for Cell PS RAB drops due to GTPU failure; check transmission alarms to identify possible faults in the Iu-PS transmission path

KPI (5): Low ISHO CS

Problem Classification

Failure Indicator

VS.IRATHO.FailRelocPrepOutCS.TAlExp.GCell

VS.IRATHO.FailRelocPrepOutCS.TgtFail.GCell Preparation phase

IRATHO.FailRelocPrepOutCS.ReloNoSup

IRATHO.FailRelocPrepOutCS.NoResAvail

Note TRELOCalloc expiry (the timer that waits for the RELOCATION COMMAND after the REOCATION REQUIRED expires; check if the RNCMSC links are normal; check CN transmission parameters) Relocation Failure in target CN/RNC or target system (check the CN configuration; check if the BSS supports the relocation) Relocation not supported in target RNC or target system No Resource Available (the BSC has no resources for the UE access or the 2G MSC has no information about the target cell)

Execution phase

IRATHO.FailRelocPrepOutCS.HigherTrafficLod Traffic load in the target cell higher than in the source cell Unknown Target RNC (the LAI of the IRATHO.FailRelocPrepOutCS.UKnowRNC 2G target cell is not configured in the MSC) Configuration Unsupported (the configuration assigned in the HANDOVER FROM UTRAN IRATHO.FailOutCS.CfgUnsupp COMMAND is not supported by the UE; check configuration of the encryption parameters; might also be UE problem) Physical Channel Failure (indicates poor 2G signal check the handover IRATHO.FailOutCS.PhyChFail thresholds in both 3G and 2G configurations; check for interference in the 2G target cell) Timeout of waiting for IU RELEASE VS.IRATHO.FailOutCS.NoReply COMMAND messages during an outgoing inter-RAT CS handover

Analysis Process:

Preparation phase Check if the RNC-MSC links are normal Check if theres any relocation failure Check if relocation not supported in target RNC or target system No Resource Available BSC has no resources for the UE access MSC has no information about the target cell Need consistency checking between 2G and 3G NDB Congestion

Execution phase Check if there are any missing 2G neighbors Check the inter-RAT handover parameters Improper settings may cause the handover not to be performed on time: events 2D/2F parameters, events 3A, 3C parameters Check the handover thresholds in both 3G and 2G configurations Database 2G-3G Consistency Check: Cross check 2G CFGMML with External 2G on 3G CFGMML (parameter check on 2G: MCC, MNC, LACCI, NCC, BCC, BCCH, RAC) Old database still not yet erased Check for Interference in the 2G target cell Check for SD and TCH blocking in the 2G target cell

KPI (6): Low ISHO PS

Problem Classification

Failure Indicator

VS.IRATHO.FailRelocPrepOutPS.TAlExp.GCell

VS.IRATHO.FailRelocPrepOutPS.TgtFail.GCell Preparation phase

IRATHO.FailRelocPrepOutPS.ReloNoSup

IRATHO.FailRelocPrepOutPS.NoResAvail

Note TRELOCalloc expiry (the timer that waits for the RELOCATION COMMAND after the REOCATION REQUIRED expires; check if the RNCMSC links are normal; check CN transmission parameters) Relocation Failure in target CN/RNC or target system (check the CN configuration; check if the BSS supports the relocation) Relocation not supported in target RNC or target system No Resource Available (the BSC has no resources for the UE access or the 2G MSC has no information about the target cell)

Execution phase

IRATHO.FailRelocPrepOutPS.HigherTrafficLod Traffic load in the target cell higher than in the source cell Unknown Target RNC (the LAI of the IRATHO.FailRelocPrepOutPS.UKnowRNC 2G target cell is not configured in the MSC) Configuration Unsupported (the configuration assigned in the HANDOVER FROM UTRAN IRATHO.FailOutPS.CfgUnsupp COMMAND is not supported by the UE; check configuration of the encryption parameters; might also be UE problem) Physical Channel Failure (indicates poor 2G signal check the handover IRATHO.FailOutPS.PhyChFail thresholds in both 3G and 2G configurations; check for interference in the 2G target cell) Timeout of waiting for IU RELEASE VS.IRATHO.FailOutPS.NoReply COMMAND messages during an outgoing inter-RAT PS handover

Analysis Process:

Preparation phase

Check if the RNC-SGSN links are normal Check if theres any relocation failure Check if relocation not supported in target RNC or target system No Resource Available BSC has no resources for the UE access MSC has no information about the target cell Need consistency checking between 2G and 3G NDB Congestion

Execution phase Check if there are any missing 2G neighbors Check the inter-RAT handover parameters Improper settings may cause the handover not to be performed on time: events 2D/2F parameters, events 3A, 3C parameters Check the handover thresholds in both 3G and 2G configurations Database 2G-3G Consistency Check Cross check 2G CFGMML with External 2G on 3G CFGMML (parameter check on 2G: MCC, MNC, LACCI, NCC, BCC, BCCH, RAC) Old database still not yet erased Check for Interference in the 2G target cell Check for PDCH blocking in the 2G target cell

KPI (6): Low IFHO PS

Failure Indicator

Note Configuration unsupported (the UE doesnt support the configuration assigned by the RNC in the PHYSICAL CHANNEL RENONFIGURATION message indicates possible UE problem however this case almost never happens in commercial networks) Physical channel failure (indicates poor coverage) Incompatible simultaneous reconfiguration (the UE feedbacks that the HHO procedure is not compatible with other concurrent processes. This case almost never happens; it indicates defective UE) Cell update occurred (this case never happens in commercial network) Invalid configuration (some IEs in the PHYSICAL CHANNEL RENONFIGURATION message are invalid for the UE; this case almost never happens; indicates possible UE problem) No response on the air interface (indicates poor coverage or even a UE problem)

Analysis Process: Optimizing Neighbor based on scenario given Blind HO setting Check availability/alarm on surroundings Check if there are any missing neighbors Check the inter-frequency handover parameters Improper settings may cause the handover not to be performed on time Check events 2D/2F parameters Check events 2B, 2C parameters